Out Past the Planets: From Pioneer 10 to Europa Clipper

Pioneer 10 launched in March 1972 and was the first mission to visit Jupiter and the first spacecraft to cross the asteroid belt. It carried a plaque meant for any intelligent life that might find it, and the last contact with it came on 23 January 2003 as its signal faded with distance.

Pioneer 11 followed in April 1973. It flew past Jupiter as the second probe to do so and became the first probe to encounter Saturn, then became one of five artificial objects to reach solar-system escape velocity. Its last good engineering data arrived in November 1995.

Voyager 2 launched in August 1977, sixteen days before its twin. It remains the only spacecraft to have visited Uranus and Neptune, and in 2018 it became the second human-made object to enter interstellar space.

Voyager 1 launched in September 1977 and is now the most distant human-made object from Earth. In 2012 it became the first to enter interstellar space, and it keeps transmitting on a shrinking power budget.

Cassini launched in October 1997 and studied Saturn, its rings and its moons from 2004 to 2017. It ended on purpose, plunged into Saturn's atmosphere on 15 September 2017 so that Enceladus and Titan stayed free of contamination.

Huygens rode to Saturn aboard Cassini and separated to descend through Titan's thick atmosphere, landing on 14 January 2005. It was the first spacecraft to land in the outer solar system, and it operated on the surface for about ninety minutes.

New Horizons launched in January 2006 and made the first close flyby of Pluto in July 2015, finding nitrogen-ice plains and water-ice mountains. In 2019 it passed the Kuiper Belt object Arrokoth, the most distant object explored up close.

Europa Clipper launched on 14 October 2024 to learn whether the ocean believed to lie under Europa's icy shell could support life. It orbits Jupiter and makes dozens of close flybys of the moon rather than orbiting Europa itself, to avoid Jupiter's intense radiation.